Wojciech Szczesny has never wavered in his belief that Arsenal will finish the Premier League season above Tottenham Hotspur. After Sunday's exhilarating 5-2 derby triumph at the Emirates Stadium, the Arsenal goalkeeper felt that his team-mates had located the spark to claw back the deficit in the table, which now stands at seven points.

"After what we have done, we believe we can challenge Tottenham," Szczesny said. "We have the momentum. Will there be psychological effects for them? As an Arsenal fan, I hope so. I said ages ago that we can't realistically win the Premier League any more but now, my main ambition is to finish above Tottenham.

"You can see that we are not any worse than them and when we have the momentum and are on the front foot, we are very dangerous. I hope we can use that to our advantage and get the momentum to start challenging."

Szczesny has endeared himself to the Arsenal support with more than his accomplished performances. The 21-year-old Pole is proud to be an Arsenal fan and he has long worn his heart on his sleeve. When he left the pitch on Sunday, he delighted in joining in, lustily, with the songs from the stands and he compared the post-match buzz to that which accompanied the Champions League victory over Barcelona last season, although that result was undermined by defeat in the second leg. It was clear that Szczesny intended to feed off the feelgood factor.

"It is comparable to beating Barcelona," he said. "It is a great feeling, probably one of the best I have ever had. I was buzzing. Every single goal felt better than the previous one and I was celebrating quite energetically, I think. But I loved it. For me as an Arsenal fan to beat Tottenham, it is the first time I have beaten them as well … it is just great."

Szczesny can always be relied upon for optimism. He pointed out that the heavy derby scoreline had followed the 7-1 drubbing of Blackburn Rovers in the previous home game and if the team could maintain their form at the Emirates, hope would spring. They have also already played away at the table's top nine clubs, apart from seventh-placed Liverpool, who they visit on Saturday.

"We are very pleased for the fans because we have let them down in the last couple of weeks," Szczesny added. "We needed that performance, not only for us but for them as well. I hope the result can transform the season."

If Tottenham had prevailed on Sunday, they would effectively have ensured a finish above Arsenal but with 12 games to play, the race feels rekindled. Tottenham's capitulation at the Emirates was shocking and they face a test of character on Sunday, when Manchester United visit White Hart Lane. Tottenham will miss the midfielder Scott Parker, who serves a one-match ban for his sending-off at Arsenal.

Rafael van der Vaart, though, fought the Tottenham corner, insisting that they remained in firm control of their destiny, as they entered a pivotal period. After United come the testing Premier League trips to Everton and Chelsea. The club's title challenge may have waned but what the manager, Harry Redknapp, described as a "bad day at the office" could not be allowed to derail the bid for Champions League qualification.

"We are still seven points ahead so we are not worried," Van der Vaart said. "We have the mental strength to put it behind us. It's just a game and we lost. It was a bad day, that's all. For the fans and for ourselves, with it being Arsenal, it always hurts but we are still third.

"Of course, you always hope but Man City are winning the games so easy … so maybe the title is over. I think third is our main goal now and I'm still really confident we will finish there."

It takes a lot to knock the belief of an international footballer and that of Szczesny extended to a pronouncement on the future of Robin van Persie. The Arsenal captain, who scored his 29th goal of the domestic season on Sunday, has said that he will not discuss a new contract until the summer, when he will have 12 months to run on his existing deal.

"We don't discuss his contract with him," Szczesny said. "But I'm personally confident that he will stay at Arsenal. That is where he belongs and that is where he is at his very best."